Braking device



June 21, 1938.

Filed Aug. 14, 1936 INVENTOR w QM. R MN r fix N M /A// g %N N\%/ Z 9% W EQ 4 NM VH a a H l5 ATTORNEY.

Patented June 21, 1938 PATENT OFFICE BRAKING DEVICE George H. Fuehren Phillipsburg, N. J., assignor to IngersollRand Company, Jersey City, N. J.,

a corporation of New Jersey Application. August 14, 1936, Serial No. 95,961

3 Claims. (m ss-4'7) This invention relates to braking devices, and more particularly to'a braking device for. the feeding mechanism of a rock drill.

One object of the invention is to prevent un- 5 authorized movement of the rock drill withrespect to the mountingwhereby it is supported.

Another object is to control the rate of movement of the rock drill with respect to its mounting. i

Other objects will be in part obvious and in part pointed out hereinafter.

In the drawing accompanying, this specification and in which similar reference numerals refer to similar parts,

5 Figure l is a longitudinal elevation of a portion of a rock drill, its mounting and the feeding mechanism controllingthe movement of the rock drill with respect to its mounting,

Figure 2 is a transverse view taken through Figure 1 on the line 2--2, and

Figure 3 is a transverse view taken through Figure 2 on the line 3-3.

Referring more particularly to the drawing, 26 designates, in general, drilling mechanism comprising a rock drill 2|, a mounting for the rock drill in the form of a shell 22 and a feeding mechanism 23 for controlling the movement of the rock drill with respect to the shell 22.

The rock drill, of which only a portion is shown,

is of the hammer type in which a reciprocatory piston 24 in a cylinder 25 actuates the working implement (not shown). The rock drill may be slidably interlocked with the shell 22, in a well known manner, and carries a nut 26 which is in threaded engagement with a feed screw 21 supported by the shell. The nut 26 may be suitably affixed to the rock drill and the threads of the nut and the feed screw are of such inclination that when a force is applied to the rock drill tending to actuate it longitudinally of the shell the feed screw 21 will be caused to rotate.

The feeding mechanism 23 is of substantially the type illustrated in United States Patent No. 1,867,929 granted to W. A. Smith, Sr., July 19,

1932. It comprises a casing 28 attached to the rearward end of the shell 22. The casing provides a bearing 29 for the feed screw 28 of which the rear end extends through the casing. The casing 28 contains suitable pawl and ratchet devices of substantially the type described in detail in the aforesaid patent and of which the ratchet wheel 3| is mounted on the feed screw.

The feed screw has a tapered portion 30 extending into a tapered bore 32 in the ratchet wheel and the extremity of the feed screw is Inaccordance with the practice of the invention, the feed screw is provided with a braking device to control the rate of feeding movement of the feed screw. The braking mechanism comprises a friction band 35 disposed, for example, about a hub portion 36 of the ratchet wheel. The friction band preferably consists of a single flexible member having a gap or space 31 between its ends which lie beneath the hub portion 36. In the periphery of the band and on opposite sides of the space 31 are notches 38 of which one forms a seat for an end of an adjusting screw 39 threaded into the casing 28 and having a lock nut 48 thereon to lock the screw 39 securely in position.

On the side of the casing opposite to that containing the screw 39 is an enlargement 4| having a recess 42 of which the outer end is provided with threads 43 for the accommodation of a hollow plug 44. Arranged within the plug 44 is a rotary member 45 having an external flange 46 at its inner end, and between the flange 46 and a shoulder 41 of the plug 44 is a friction member 48 against which the adjacent end of the flange 46 bears. The rotary member 45 extends exteriorly of the plug 44 and carries a lever 49 whereby the rotary member may be rotated.

In the inner portion of the rotary member 45 is a threaded recess 58 to accommodate the threaded end 5| of an actuator or transmission member 52 slidable in the casing and engaging, with its opposite end, the notch 38 in the adjacent portion of the friction band 35. On the periphery of the actuator is a flange 53 carrying lugs 54 which extend slidably into notches 55 in the recess and engage the surfaces defining the notches 55 for preventing rotation of the actuator 52 with respect to the casing. A spring 56 seated upon the innermost wall of the recess 42 and the flange 53 acts constantly to press the flange 45 against the friction member 48.

In the operation of the device and with the piston 24 of the rock drill-in action the jars resulting upon reversal of the piston in the ends of the cylinder are transmitted to the casing of the rock drill and tend to actuate the rock drill longitudinally of the feed screw 21. The direcas may be ascertained by reference to the hereinbefore mentioned patent.

It may be stated herein, however, that when the control member 34 occupies one controlling position the shocks to which the rock drill is subjected by the piston 24 during its reversal in one end of the cylinder will cause the feed screw to rotate in one direction and a reverse movement of the feed screw may be obtained by shifting the control member to another limiting position, it being understood, of course, that the threads of the feed screw and the nut are of non-locking inclination.

If, during the operation of the drilling mechanism, a comparatively slow feeding movement of the rock drill be required the rotary member may be rotated to move the actuator 52 in the direction of the screw 39 and thereby contract the friction band 35 on the hub 36. The degree of rotary movement of the rotary member depends, of course, upon the braking force required, but such movement of the rotary member 45 does not alter its position with respect to the friction member 48 against which it is constantly pressed by the spring 56. The rotary member will, therefore, remain immovable in all positions unaffected by the vibrations incident to the operation of the rock drill.

In operations requiring the arrangement of the drilling apparatus in a vertical position, as when drilling downholes, the braking device may serve to hold the feed screw immovable. In such case the brake manipulating devices are adjusted to lock the friction band 35 on the hub portion 36.

ment and obviates the chances of injury to the attendant.

I claim:

1. A braking device, comprising a casing, a brake band therein, extensible means for imparting braking action to the brake comprising a rotary member and a non-rotary member in engaging contact with the brake band and being in slidable engagement with the casing, and means for efiecting movement of the non-rotary member longitudinally of the rotary member upon rotation of the rotary member.

2. A braking device, comprising a casing, a brake therein, an actuator for the brake slidably interlocked with the casing, a rotary member in the casing in threaded engagement with the actuator for shifting the actuator, a friction member in the casing, and a spring for pressing the rotary member into frictional engagement with the friction member to prevent unauthorized movement of the rotary member.

3. A braking device, comprising a casing, a braking band, an actuator for the braking band slidable in the casing, interlocking means on the actuator and the casing to prevent rotary movement of the actuator, a rotary member in the easing in threaded engagement with the actuator for shifting the actuator, a flange on the rotary member, a friction member in the casing for the flange, and a spring acting against the casing and the actuator to press the flange into frictional engagement with the friction member.

GEORGE H. FUEHRER. 

